(I accidentally and idiotically deleted this comment and now DW isn't letting me re-post it, so here is some added text so it's a different comment.)

This gets customized before you drag it to your bookmarks bar (or alternatively before you copy-paste the userscript configuration that's generated below the bookmarklet).

• Select each attribute that you want to be included in your Pinboard bookmark's tags, fine-tuning if need be with the options that open up when you select something.
  
• If you select Include author's summary - only if no text on the page is selected. the bookmarklet will automatically put the summary into the body of the Pinboard bookmark.
  
  • f you select text in the fanwork before clicking the bookmarklet, that text will be added to the body of the bookmark, rather than the summary.
  
  
• You can generate the bookmarklet repeatedly until you find the version you like. Just delete the old one from your bookmarks bar before dragging the new one up.